Lost sync reason 2 over 6000 rpm

[therealpinto]

Hi

Last week I had my turbo Capri on the dyno, and right away we spotted a problem with misfires around 6300 rpm. The log files showed that pw went to 0 but we did not have time to investigate further, so we kept the revs below that. On the dyno day the problem was the same with and without load.

Now I have captured some more log files and I'm trying to learn more about the issue. I could not replicate the problem without load, but when driving, under full boost, it's the same.

The logs show lost sync reason 2 (missing tooth at the wrong time). Is it likely that the sensor is the fault?

I am using a YB Cosworth VR sensor, it's used with a 4 teeth trigger wheel in the standard configuration but I run a 36-1 wheel. The YB sensor is very convenient since it fits a standard YB mount but I can make a mount for an EDIS VR sensor instead (made for 36-1). But before I try that it would be nice with a second opinion.

I run MS3 with MS3X, shielded wire for the VR, MS grounded to the engine, Quadspark ignition module and EDIS coil. The engine is a 2.0 Pinto.

You can see it in the log file at 1472 s and in the composite log at around 11070 ms.

Thanks in advance

Gustaf

[grom_e30]

the composite logger catches it twice once on page 24 and the second time on 26 both times the sensor is failing to see the 12th tooth after the missing gap.

[therealpinto]

Yes, and it sort of happens every time in that rev range. A bit hard to get several runs at over 6000 rpm though, roads are cold and grip is not that great.

The question is if it is likely to be hardware (VR sensor) or something else. But I guess I might have try another VR sensor to find out.

Thanks

Gustaf

[grom_e30]

if its an after market toothed wheel have a look at the 12th tooth anti clockwise from the missing tooth just to make sure its not bent slightly or has a slightly bigger air gap than the rest.

[jsmcortina]

Or perhaps a bolt head beside it or something?

James

[therealpinto]

Thanks for some good input!

I will check the trigger wheel, however, it is quite beefy:







Gustaf

[therealpinto]

Update:

I tried fitting a VR sensor from a EDIS system but it's polarity is reversed (or seems to be) vs. the YB Cosworth sensor. I made a pigtail to swap polarity but did not get it to give a consistant signal at all.

Put the YB sensor back and tried adjusting the VR pot (R56), at first I had trigger faults lower down in the rev range but after a few half-turns clockwise I got it to run smooth up to 7100 rpm with no sync loss. Only tried once since it is freezing now, impossible to not spin in second and third (and 7100 rpm in fourth is not something for public roads).

But it seems to be working and it seems to be a user fault?

Regards

Gustaf

[capri v8 driver]

Hello Gustaf.

if the problem stays or comes back you could try to add a 10k or 20k resistor in the ve+ of the VR sensor.